Where are the Lawns in the US?

Home’s that already have lawns are prime candidates for foodscapes. The total surface area devoted to lawns is about 1 trillion square feet, more than enough space to radically impact food production in the US if it were harnessed.

Where are these lawns? Clustered around urban areas as this NASA map shows (here’s the hi-res version). They cost $30-40 billion a year to maintain.